This subject has been done to death so many times, but has anybody actually DONE it??
BRNAV approval is not an issue - this is old hat and many reasonably recent planes (e.g. the TB20) have had a BRNAV GPS (KLN94 or GNSx30 in this case) installed under the original type certificate. Simply screwing a GPS (of the type on the original TC) into the panel, with an appropriately positioned CDI, will yield a BRNAV approved installation.
But for flying GPS
approaches one needs the custom POH supplement which (for a G-reg) needs to be EASA approved and there have been various threats of it being a Major Mod. I have so far not heard of
anybody who has got this in their hand. If they do, I would like to actually see it, who they got it from and how much they paid for it (confidentially of course). If somebody has actually got one they will of course know all about it, and the cost.
For an N-reg, the GPS approach requirement is met with an FAA approved POH supplement too. This is VERY old hat in the USA (well over 10 years old) but I have so far not heard of anybody who has got this done in the UK. I did hear from one chap who claimed to have got it done via FAA at Heathrow but my investigation has drawn a blank and his own avionics shop denies any knowledge of it (well this is GA after all...) but they do remember a case a few years back where the application had to be sent to the USA and "cost a packet". I tried to obtain a custom POH supplement for my GPS via this same (well known) shop but despite many reminders they washed their hands of it. I told them to do it within a £500 budget or at least let me know the cost but they couldn't be bothered.
So.... for all the talk talk talk more talk, everywhere, my guess is that nobody actually cares - unsuprising since there are no useful GPS approaches anywhere in Europe. By "useful" I mean at airports where there isn't a conventional approach which can be flown (without spending any money on custom POH supplements) using either the Jepp "overlay" depiction or by using the OBS mode
